I have a 2005 equinox. The ac works fine if you leave the blower on 1or2 but if you turn to 3or4 the blower speeds up but the ac compresser turs off. can not get the car cooled off on these low settings.

 

I didn't know the two were related. I see in my manual 2000-2006 full size the compresor relay, but don't know what all controls it the schematic dsoen't show.

 

Have you actually looked to see that the A/C compressor is in fact shutting off?
Does the A/C LED on the A/C button go out?

The blower motor circuit is not a factor in the A/C compressor circuit and operation.

I've attached a couple diagrams below along with a description of operation of the air temp controls. The description tells the conditions for which the A/C compressor is turned off.

For future readers, the information in the diagrams is only applicable to 2005-2006 Equinox.

2005-2006__Chevrolet_Equinox_AC_Compressor_Circuit.pdf
2005-2006__Chevrolet_Equinox_HVAC_Circuit.pdf
2005-2006__Chevrolet_Equinox_Air_Temp_Description_and_Operation.pdf

 

well i didnt fall off the turnip truck. i know how to tell if the compresser turns off. Took to dealer today. He called at 4pm to tell me i needed a body control relay. going to be about 400 still have never heard of a body control relay???

 

Sounds like they want you to replace the Body Control Module. Since the A/C compressor does come on if one of the two lower blower settings is selected, I'd be inclined to think that the BCM is working fine and that the HVAC control module is not sending an A/C request signal when the blower is set to one of the two higher speeds. Of course this is assuming that everything else is in working order and all conditions are met to allow the compressor to be engaged.

If I were a betting man without knowing anything else, my money would be on a bad HVAC control module, not a bad BCM. Usually BCMs fail in a catastrophic manner that affects the functionality of many circuits, not just one.

EDIT: Sure enough, GM issued TSB #04-01-38-006 for this issue which says to replace the blower motor resistor or the HVAC control module if resistor tests fine.

TSB_#04-01-38-006.pdf